Effective animal stunning

ABSTRACT

An animal stunning apparatus for inducing unconsciousness and insensibility of a live subject animal includes an applicator for contacting an application point on the live subject animal&#39;s head and couples microwave radiation to the head. A microwave generator generates microwave energy of a suitable power level and frequency, and a waveguide directs the microwave radiation to the applicator. An auto-tuner in the waveguide uses a directional coupler to detect forward and reflected power and to tune in real time the impedance for matching the load and optimize effective power transfer. A switch discontinues the application of microwave radiation that is heating the frontal portion of the brain after a period of time sufficient to induce the unconsciousness and insensibility. Methods for inducing rapid unconsciousness and insensibility in an animal include application of microwave radiation.

CROSS-REFERENCE TO PRIOR APPLICATIONS

This application is a national phase entry under 35 U.S.C. §371 ofInternational Patent Application PCT/AU2013/001271, filed Nov. 4, 2013,designating the United States of America and published in English asInternational Patent Publication WO 2014/066953 A1 on May 8, 2014, whichclaims Convention priority from U.S. patent application Ser. No.13/668,030, filed Nov. 2, 2012, now U.S. Pat. No. 8,506,355, issued Aug.13, 2013, the disclosure of each of which is hereby incorporated hereinin its entirety by this reference.

TECHNICAL FIELD

This disclosure relates to methods and apparatus for stunning of animalsto induce unconsciousness and insensibility enabling processing orhandling of the animal.

BACKGROUND

In slaughtering a live animal in an abattoir for production of meat,hide, and other by-products, the animal is usually restrained and thenstunned to induce immediate unconsciousness and insensibility. Theslaughter can then be performed without avoidable fear, anxiety, pain,suffering and distress. The stunning can also help avoid difficultiesand dangers for persons involved in the processing and handlingoperations.

The “stunning” is commonly carried out either by an mechanical process,such as applying concussion by means of a projectile captive bolt(penetrating or non-penetrating mushroom headed knocker) impactedagainst the skull of the animal, or by electrical current applied to theanimal and passed through the brain, or by inhalation of gases such ascarbon dioxide, nitrogen or argon.

The terms “stun” or “stunning” are frequently used to refer toirreversible processes, i.e., the “stunning” process causes irreversibledamage to the animal, particularly the brain. This may not be adifficult or contentious issue with regard to animal welfare concernsbecause the slaughter, such as by sticking and exsanguination,immediately follows the stunning and is, therefore, performed on anirreversibly unconscious and insensible animal.

However, with religious slaughter or ritual slaughter, irreversiblestunning is not acceptable. The animal must not be injured or harmedprior to exsanguination. For example, with the Muslim slaughter methodor “Halal slaughter,” the animal is required to be alive at the time ofslaughter. This requirement does not necessarily mean that the animal isnot permitted to be first stunned prior to slaughter, as long as thereis no injury, e.g., significant damage to the skull, but irreversiblestunning may well be unacceptable to comply with the dictated ritualrequirements. Likewise with the Jewish or Judaic slaughter method or“Shechita,” post-cut stunning of the animal may be permissible, but notirreversible pre-cut stunning that may be deemed unacceptable so thatthe resulting carcass would not be Kosher.

There have been some references in the published patent literature touse of microwave radiation stunning of animals for slaughter.

U.S. Pat. No. 3,973,290 refers to stunning an animal for slaughter byapplying microwave energy to penetrate the animal's skull and heat thebrain. A microwave beam is proposed to be directed at the animal withoutrestraining it, the energy being applied from the side of the skull.Such methods of application would create considerable surrounding tissuedamage by largely indiscriminate heating and, therefore, would be anirreversible process, causing harm to the animal, and is likely to beinhumane.

U.S. Pat. No. 4,616,160 describes a microwave heating apparatus forirradiating the entire head of test animals, particularly rodents. Theconfiguration of the apparatus including the manner of coupling themicrowave energy to the animal will heat the entire head of the animal.The specification does not explain whether the purpose is to stun theanimal but, if so, many organs and tissues of the head are likely to bedamaged and the apparatus would, therefore, be unacceptable from thepoint of view of animal welfare.

DE 4116670 describes and illustrates an apparatus for irradiating a pigwith multiple microwave applicators arranged around the head and in arow along the length of the spine, all being spaced from the animal. Useof such an apparatus design will irreversibly damage tissues by cookingaffected tissues, which is likely to be inhumane.

JP 3039615 describes apparatus for slaughtering animals using microwavesto heat the brain causing cerebral death.

WO2011/137497 describes an animal stunning apparatus and method forinducing rapid unconsciousness and insensibility. The apparatus includesa stunning station in which a live subject animal is located in aconfined position and an applicator contacts an application point on thelive subject animal's head immediately overlying a frontal portion ofthe animal's brain and couples microwave radiation to the head. Amicrowave generator generates microwave energy of a suitable power leveland frequency, and a waveguide directs the microwave radiation to theapplicator. A switch discontinues the application of microwave radiationeffecting heating of the frontal portion of the brain after a period oftime sufficient to have raised the temperature of the frontal portion ofthe brain of the subject animal to thereby induce the unconsciousnessand insensibility. The period is sufficient only to rapidly induceinsensibility, and is insufficient for the insensibility induced to beirreversible, and insufficient to cause significant heating of deeperbrain tissues, including the brain stem. This system is owned by thepresent applicant and testing and development of this system revealedsignificant and unexpected difficulties in achieving consistent resultsfor the animal stunning, making the system unsatisfactory commerciallyand/or for animal welfare.

The above references to and descriptions of prior proposals or productsare not intended to be, and are not to be construed as, statements oradmissions of common general knowledge in the art in Australia orelsewhere. None are known to have ever been commercially used.

BRIEF SUMMARY

It is an object of the present disclosure to provide processes andapparatus for stunning of animals to effectively and more consistentlyinduce unconsciousness and insensibility.

It is a particular preferred object to provide processes and apparatuscapable of stunning of animals to induce rapid unconsciousness andinsensibility in an effective and controlled manner that the stun isreversible, meaning that the animal can later regain consciousness andsensibility without significant loss of brain-mediated functionincluding motor functions, sensory processing, innate and instinctivefunctioning, learned behavior, etc. With such reversible animal stunningprocesses and apparatus, animals for slaughter can be stunned in amanner to enable subsequent processing and handling, includingslaughter, while the system still remains compliant with certainreligious slaughter rituals. The achievement of reversible stunningprocesses and apparatus may also enable such stunning of animals forother kinds of processing or handling, such as for veterinaryinspections or purposes, banding, branding, tagging, inspectionrecording and re-release, etc. However, the particular processes andapparatus described herein will refer to the primary intended field ofapplication, namely slaughtering of animals for food production, hiderecovery and treatment, and other by-product extraction and processing.

According to the first aspect of the present disclosure, there isprovided a method of stunning an animal for inducing unconsciousness andinsensibility enabling processing or handling of the animal, the methodincluding the steps of:

-   -   introducing a live subject animal to be processed or handled to        a stunning station and locating the animal in a generally        confined position,    -   locating an applicator in contact with an application point on        the animal's head immediately overlying the frontal portion of        the subject animal's brain, the applicator having a coupling        conformation to couple microwave radiation through the        applicator to the head and to the frontal portion of the brain        of the subject animal,    -   generating microwave radiation of a suitable power level and        frequency and directing that radiation through a waveguide to        the applicator at an operative end of the waveguide to thereby        heat the frontal portion of the brain of the subject animal,    -   detecting reflected power of microwave radiation in the        waveguide and, in response to the level of reflected power,        tuning the waveguide so as to reduce the reflected power being        detected by changing the impedance of the waveguide and        applicator to better match the impedance of the head and thereby        increase the transfer of microwave power to the head, and    -   continuing the application of the microwave radiation to effect        the heating for a period of time to raise the temperature of the        frontal portion of the brain, the period being sufficient to        induce insensibility.

For compliance with ritual slaughter criteria, the switch can beoperable to discontinue the application of microwave radiationimmediately after a period that is sufficient only to rapidly induceinsensibility, and insufficient (i) for the insensibility induced to beirreversible, and (ii) to cause significant heating of deeper braintissues, including the brain stem.

Preferably, the application point is medially located on the head of thesubject animal above a line extending between the animal's eyes so as tobe located at the closest external point to the central and frontalportion of the brain. Preferably the frontal portion of the brain of thesubject animal is heated to satisfy at least one of the conditions: thetemperature increases by an amount in the range of about 5° C. to about10° C., and the temperature increases to about 43° C.

In a particular preferred embodiment, a period of time during whichapplication of the microwave radiation is continued and during which thetuning is continually performed is terminated after a period for aneffective power transfer defined as sufficient to achieve an effectivesyncope of the animal, the effective power transfer being determined asa function of power transferred to the animal and excluding reflectedpower. In this embodiment, the method preferably includes the steps ofmeasuring continually the power of microwave radiation being reflected,and determining from the power generated by the microwave generator andfrom the measured reflected power the actual power being transferredfrom the applicator.

In one possible method according to this preferred embodiment, theeffective power transfer is reached by applying microwave power for apredetermined time period, which is started only after the power beingtransferred through the applicator is determined to have reached apredetermined level. In an alternative method, the effective powertransfer is reached by applying microwave power for a time periodsufficient for the sum of the determined power levels being transferredthrough the applicator for a plurality of time increments to reach apredetermined sum.

The detection of microwave radiation reflected in the waveguide ispreferably performed using a directional coupler associated with thewaveguide and operable to measure the complex reflection coefficient ofthe load, thereby enabling determination in real time of the power beingtransferred through the applicator.

For enabling monitoring of the effective power transfer and visualassessment of an effective syncope, the method preferably furtherincludes the step of visually displaying the microwave power beinggenerated by the microwave generator during the stunning operation, themicrowave power being detected as reflected within the waveguide andarising from the degree of the impedance matching with the head, and thepower determined from the generated and reflected power as beingtransferred through the applicator throughout the stunning operation.

The method also preferably further includes the step of continuallylogging the microwave power being generated by the microwave generatorduring the stunning operation, the microwave power being detected asreflected within the waveguide and arising from the degree of theimpedance matching with the head, and the power determined from thegenerated and reflected power as being transferred through theapplicator throughout the stunning operation so as to provide a storedrecord of parameters of the stunning operation for subsequent analysisfor regulatory compliance, process research, and operation managementpurposes.

According to a second aspect of the disclosure, there is provided ananimal stunning apparatus for inducing substantially immediateunconsciousness and insensibility, enabling processing or handling of asubject animal, the apparatus including:

-   -   a stunning station to which a live subject animal to be        processed or handled is introduced, the stunning station being        arranged to locate the subject animal in a confined position;    -   an applicator located so as to contact an application point on        the live subject animal's head immediately overlying a frontal        portion of the animal's brain, the applicator having a coupling        conformation to couple microwave radiation therethrough to the        head and to the frontal portion of the brain of the subject        animal when in the confined position at the stunning station;    -   a microwave generator for generating and radiating microwave        energy of a suitable power level and frequency;    -   a waveguide coupled to the generator so as to receive and direct        the microwave radiation to the applicator located at an        operative end of the waveguide so as to thereby heat the frontal        portion of the brain of the subject animal beneath the        application point that the applicator contacts in use; and    -   a switch operable so as to discontinue the application of        microwave radiation effecting heating of the frontal portion of        the brain after a period of time sufficient to have raised the        temperature of the frontal portion of the brain of the subject        animal to thereby induce the unconsciousness and insensibility,        and    -   wherein the apparatus further includes an auto-tuner operatively        associated with the waveguide and that detects reflected power        of microwave radiation in the waveguide resulting from the        degree of the impedance matching between the applicator and the        head and that tunes the waveguide to reduce the reflected power        and increase the transfer of the microwave power to the head.

Preferably, the auto-tuner is operable in an iterative manner tocontinually tune the waveguide during the application of microwaveradiation so as to continually improve or maintain impedance matchingwhile the impedance of the head changes due to heating.

In a preferred embodiment of the apparatus, the applicator has anopening therein through which the microwave radiation from the waveguideis coupled to the animal's head at the application point, the peripheralportions of the applicator defining the opening contacting the animal'shead to surround the application point when the applicator is in itsoperative position. Preferably, the peripheral portions of theapplicator are yieldable so as to conform in shape to the shape of theanimal's head at the application point upon relative operativepositioning of the applicator at the application point. The peripheralportions of the applicator are preferably flexible so as to yield andconform to the surface shape of the animal's head at the applicationpoint, the flexible peripheral portions of the applicator beingimpermeable to microwave radiation.

In one possible construction, the peripheral portions of the applicatordefining the opening are composed of metallic braid so as to be flexibleto conform to the surface shape, to be impermeable to microwaveradiation, and to be resilient to substantially return to an initialstate after the removal of the applicator from the application point.

Alternatively or in addition to a yieldable peripheral portion at theopening, the waveguide or applicator may include a movable jointenabling limited movement of the applicator to improve contact of theperipheral portions of the applicator defining the opening for differentrelative positions and conformations of the animal's head and to limitmicrowave leakage at the application point. In this construction, themovable joint may enable limited movement of the applicator about twoorthogonal axes, which are generally parallel to the surface of theanimal's head at the application point where the animal's head ispresented for contact with the applicator.

The apparatus may further include a head detector switch mounted by theapplicator and operable to switch its state only upon achievement ofpositive sealing contact of the applicator with the animal's head at theapplication point. The switch may be operable to changes its state onlyupon deformation of the flexible peripheral portions of the applicatordefining the opening being flexed to an extent achieved when closecontact of the applicator with the surface of the animal's head at theapplication point has been achieved, the switch being connected in acircuit preventing commencement of application of microwaves to theanimal's head until the switch has changed its state, indicative ofeffective sealing contact of the applicator with the animal's head.

BRIEF DESCRIPTION OF THE DRAWINGS

Possible and preferred features of the present disclosure will now bedescribed with particular reference to the accompanying drawings.However, it is to be understood that the features illustrated in anddescribed with reference to the drawings are not to be construed aslimiting on the scope of the disclosure. In the drawings:

FIG. 1 is an illustration of a cattle head with the application pointfor the microwave radiation indicated.

FIG. 2 schematically illustrates in side view an animal stunning stationwith stunning apparatus according to one embodiment of the disclosure.

FIG. 3 schematically illustrates in side view an animal stunning stationwith stunning apparatus according to a second embodiment of thedisclosure.

FIG. 4 is a detailed side view of the outlet end of a microwaveapplicator, which is applied to the animal's head.

FIG. 5 is a view of a graphical display at the control station enablingviewing of parameters to ensure effective stunning.

DETAILED DESCRIPTION

The illustrated apparatus of FIG. 2 is mostly the same as that describedand illustrated in the applicant's specification WO2011/137497 andreference may be made to that specification for more detail thandescribed here. In summary, however, the apparatus includes an animalstunning station 10, which includes an enclosure 11 or crush. The animalis introduced into the enclosure through entrance 12 and confinedtherein between the entrance 12, which has a door that closes behind theanimal. An opening 20 at the head end 17 of the enclosure 11 enables theanimal to place its head 50 through the opening. The stunning station 10includes head positioning means 25 to locate and present the animal'shead 50 in a defined position to the microwave applicator 60. Theapplicator point 51 where the microwave radiation is to be applied bythe applicator 60 is, as shown in FIG. 1, medially located on the headabove a line extending between the animal's eyes so as to be located atthe external point closest to the central frontal portion of the brain.

The embodiment of FIG. 3 will include the same or similar elements tolocate, restrain, and support the animal, but to simplify the drawingthese are not illustrated.

The stunning station in the illustrated apparatus of FIGS. 2 and 3locates the animal in the confined position so that the applicator 60can contact the application point 51 immediately overlying a frontalportion of the animal's brain. The applicator 60 has a couplingconformation 61 to couple microwave radiation therethrough to the head50 of the animal. A microwave generator 75 generates and radiatesmicrowave energy of a suitable power level and frequency. Waveguide 76is coupled to the generator so as to receive and direct the microwaveradiation to the applicator 60 located at an operative end 77 of thewaveguide. Switching means 78 (schematically shown in FIG. 2 and beingpart of the controller 40 in FIG. 3) is operable to discontinue theapplication of microwave radiation effecting the heating of the frontalportion of the brain after a period of time sufficient to raise thetemperature of the frontal portion of the brain of the animal to therebyinduce unconsciousness and insensibility or syncope.

If the animal is to be stunned for ritual slaughter requiring the animalto be alive, or if the animal is to be held insensible for a time, e.g.,for performing veterinary tests or processes, after which the animal isto be returned to its normal sensible and conscious condition byallowing the temperature of the front portion of the brain to return tonormal, the switching means 78 is operable to discontinue theapplication of microwave radiation immediately after a period that is:

-   -   sufficient only to rapidly induce insensibility and    -   insufficient        -   (i) for the insensibility induced to be irreversible, and        -   (ii) to cause significant heating of the brain tissues,            including the brain stem.

FIGS. 2 and 3 schematically illustrate the waveguide 76 provided with anassociated auto-tuner 90 to improve the tuning efficiency andeffectiveness between different animals being processed and to enableadjustment of the tuning as the dielectric properties of the animal'shead changes with temperature. As the research has discovered, animalheads have different impedances, with numerous variables affecting thatproperty, such as animal breed, age, sex, physical features ofindividual animals such as different tissue thicknesses and compositions(bone, muscle, fat, hide, etc.), different shapes of head, differentsurface features and surface materials (fur, wool, hair), differenttemperatures (at the start and during microwave application), andmoisture content. Tuning of the impedance of the waveguide andapplicator to each animal head as it is presented has been conceived andfound to be beneficial.

The auto-tuner 90 in FIG. 2 includes a directional coupler 91 mounted toand operatively associated with the waveguide 76. The directionalcoupler 91 associated with the waveguide is operable to measure thecomplex reflection coefficient of the load, thereby enablingdetermination in real time of the power being transferred through theapplicator 60. For example, the coupler samples the standing wave in thewaveguide, e.g., by providing probes 92 at spaced points lengthwise ofthe waveguide, optimally at 60° intervals of the guide wavelength. Thecoupler 91 provides data signals to the processor 94, which can beconstructed or programmed to analyze the signals from the coupler 91 andto determine forward and reflected power levels. A target reflectedpower level may be programmed for the apparatus to achieve by tuning ofthe waveguide. Effectively, the coupler 91 and associated processor 94are determining the impedance by determining the complex reflectionco-efficient of the microwave load (i.e., the head 50).

The apparatus also includes a tuner 96 associated with the waveguide 76,which is responsive to the processor 94. The tuner may, for example,comprise movable members 97 having associated drives 98 so that, inresponse to command signals from the processor 94, the drives 98 movethe respective positions of the members 97 within the waveguide 76,thereby altering the impedance characteristics of the waveguide. Thedirection and extent of the movements of the members 97 are controlledby the processor so as to adjust the impedance of the waveguide in amanner to reduce the reflected power toward the programmed target andthat will indicate improved effective coupling of the microwaves to thehead 50.

Each animal head 50 has a different impedance, e.g., due to differencesin the sizes and composition of the heads, and due to the positions ofthe heads in relation to the applicator 60. As soon as power is applied,the auto-tuner 90 begins analyzing the impedance and adjusting the tuner96 so as to improve the impedance matching between the waveguide 76 andapplicator 60 and the load, i.e., the head 50. As the application ofmicrowave radiation to the head 50 occurs and warming of the head andfrontal brain tissues begins, the impedance of the head 50 will change.Therefore, the auto-tuner 90 is operative to continually monitor thereflected power and to automatically adjust the tuner 96 and maintain orimprove the power coupling to the head 50. Thus, by automatic impedancematching between the waveguide and applicator and the head at thecommencement of the stunning operation, and by continually monitoringand auto-tuning of the waveguide in an iterative manner to maintainimpedance matching, the rate of heating of the animal head 50 andparticularly of the frontal brain region, can be increased, thusdecreasing the duration of the heating time necessary to induceunconsciousness and insensibility.

Referring to the embodiment of FIG. 3, the same reference numerals areused for the same components as FIG. 2. However, in this embodiment, asupervisory controller 40 is incorporated to significantly improve theeffectiveness of the animal stunning operations. A function of thecontroller 40 is to determine the period of time during whichapplication of the microwave radiation is continued and during which thetuning is continually performed by the auto-tuner 90 after there hasbeen an effective power transfer defined as sufficient to achieve aneffective syncope of the animal. In particular, the effective powertransfer is determined by a function of power transferred to the animaland excluding reflected power. The data from the directional coupler 91and the processor 94 enable the power of microwave radiation beingreflected to be measured continually, and from the power generated bythe microwave generator 75 and from the measured reflected power, theactual power being transferred from the applicator 60 can be determinedby the processor 94 or by the controller 40, which receives datacontinually from the auto-tuner 90.

As shown in FIG. 5, a graphical display 45 is provided at the controlstation where the controller 40 is located, the display enabling viewingof parameters to ensure effective stunning. In FIG. 5, the display is aplot generated in real time of power as a function of time. There arethree superimposed plots:

-   -   forward power “Pf” representing the microwave power detected by        the directional coupler 91 being generated and transferred by        the waveguide,    -   reflected power “Pr” representing the microwave power detected        by the directional coupler 91 being reflected within the        waveguide, primarily arising from impedance mismatch with the        load, and    -   transferred power “Pe,” which substantially equates to the power        being absorbed by the load (if there is little leakage of        microwave power at the application point) and which can be        computed as the difference between the forward or generated        power and the reflected power.

It can be seen that the reflected power Pr falls to zero only after aperiod of time as the auto-tuner proceeds to match the impedances of thewaveguide and applicator with the load (animal's head). The time takento fall to zero is desirably minimized but without prejudice to theachievement of an effective stun, so the period of effective applicationof microwave power is not solely a function of time that the generatoris operating. The curve Pe is more significant in determiningeffectiveness.

In order for the process and apparatus to ensure the effective powertransfer defined as sufficient to achieve an effective syncope of theanimal is reached, the controller in one embodiment applies microwavepower for a predetermined time period, which is started only after thepower being transferred through the applicator 60 is determined to havereached a predetermined level. This is shown in FIG. 5 by the levelmarked “Pmin,” which can be the power level that the Pe measurement mustreach before the timer starts.

In an alternative possible embodiment, in order for the process andapparatus to ensure the effective power transfer defined as sufficientto achieve an effective syncope of the animal is reached, the controller40 applies microwave power for a time period sufficient for the sum ofthe determined power levels Pe being transferred through the applicator60 for a plurality of time increments dt to reach a predetermined sum.Effectively, the controller is computing in real time an integralrepresenting the area under the plot of the Pe level, which can providea more accurate measure of power absorbed by the load 50 than, say, thecrude power generated by the microwave generator 75 or the forward powerPf. When a predetermined sum or value of the integral is reached, theapplication of power is stopped.

By visually displaying during the stunning operation the microwave powerPf being generated by the microwave generator 75, the microwave power Prbeing detected as reflected within the waveguide 76 and arising from thedegree of the impedance matching with the head 50, and the power Pedetermined from the generated and reflected power as being transferredthrough the applicator 60 throughout the stunning operation, monitoringof the effective power transfer and visual assessment of an effectivesyncope are possible.

The system in FIG. 3 includes a memory or storage 48 in which thecontroller 40 continually logs during the stunning operation (1) themicrowave power Pf being generated by the microwave generator 75 andtransmitting through the waveguide 76, (2) the microwave power Pr beingdetected as reflected within the waveguide 76 and arising from thedegree of the impedance matching with the head 50, and (3) the power Pedetermined from the generated and reflected power as being transferredthrough the applicator 60 throughout the stunning operation so as toprovide a stored record of parameters of the stunning operation forsubsequent analysis for regulatory compliance, process research, andoperation management purposes.

Other data will also be recorded and stored in a functioninginstallation such as individual animal identification associated withthe respective log of a stun performed. Data display and logging canalso include, for example, the complex reflection coefficient displayedin various formats, including magnitude, phase, return loss, VSWR, polardisplay, as well as measurements of incident, reflected and absorbedpower. Other process data and apparatus operational data will also bestored, together with operator information and recordable comments forlater regulatory compliance assessment, system maintenance and operationreview, process refinement and development, etc. These functions areknown for industrial control systems such as SCADA (supervisory controland data acquisition) systems. Such SCADA systems have HMI (humanmachine interfaces) that present processed data to a human operator andthrough which the operator monitors and controls the stunning processes.

Auto-tuners suitable for use in the apparatus of the present disclosuremay be composed of a “Homer Analyzer” (an automatic impedance and powermeasurement system) such as the Homer Autotuner Stolpa, Model STHT v2,3,from S-TEAM Lab, Slovak Republic, which is operatively coupled to amotorized tuner such as one obtained from, or analogous to those madeby, Muegge GmbH (Reichelsheim, Germany).

In FIGS. 2 and 3, the applicator 60 is illustrated without detail of itsconstruction and configuration. However, it has an opening 62 throughwhich the microwave radiation from the waveguide 76 is coupled to theanimal's head 50 at the application point 51. There are peripheralportions of the applicator defining the opening 62 that contact theanimal's head so as to surround the application point 51 when theapplicator 60 is in its operative position. The configuration of theopening 62 is chosen with consideration to providing impedance matchingbetween the impedance of the applicator 60 and the tissues at theapplication point 51. The area bounded by the peripheral portions 63 arecomposed of shielding material, typically metal, to provide powertransfer to the animal tissues without microwave leakage.

In WO2011/137497, FIG. 4, the peripheral portions 63 are composed ofshielding material and are configured so as to project slightly beyondthe opening 62 so that they press into the surface tissues of theanimal, typically by about 1 to 2 mm, with the aim of achieving goodcoupling and microwave energy transfer without leakage and also toresist transverse movement of the applicator 60 if the animal attemptsto move its head particularly generally in the plane of the opening 62.However, the considerable variability of animal head conformations hasbeen found to enable microwave leakage even with a firm pressure of theapplicator against the animals' heads.

The applicator 60 shown in the present FIG. 4 comprises peripheralportions 63 surrounding the opening 62 of the applicator 60, which areyieldable so as to conform in shape to the shape of the animal's head atthe application point upon relative operative positioning of theapplicator 60 at the application point. In the illustrated embodiment,the peripheral portions 63 of the applicator are flexible so as to yieldand conform to the surface shape of the animal's head at the applicationpoint, the flexible peripheral portions of the applicator beingimpermeable to microwave radiation.

In the embodiment of FIG. 4, the peripheral portions 63 of theapplicator 60 defining the opening 61 are composed of metallic braid soas to be flexible to conform to the surface shape, so as to beimpermeable to microwave radiation, and so as to be resilient tosubstantially return to an initial state after the removal of theapplicator from the application point. The braid 64 may be wound arounda resilient core such as a resilient rubber or polymer tube, like apressure hose used, for example, in pneumatic or hydraulic applications.Other constructions of the peripheral portions 63 of the applicator 60are possible, such as a flexible metallic foil skirt, or a mesh that isflexible or deformable and surrounds the opening 62.

In addition to, or as an alternative to, the flexible peripheralportions 63 surrounding the opening 62, the waveguide 76 or applicator60 can include a movable joint 66 enabling limited movement of theapplicator to improve contact of the peripheral portions 63 of theapplicator defining the opening 62 for different relative positions andconformations of the animal's head and to limit microwave leakage at theapplication point. As illustrated in FIG. 4, for example, the movablejoint 66 can be constructed and operable to enable limited movement ofthe applicator about two orthogonal axes X and Y, which in use, aregenerally parallel to the surface of the animal's head at theapplication point where the animal's head is presented for contact withthe applicator. The particular joint 66 shown resembles a concertinaformation of a section of the passage of the waveguide or applicator,but other joint constructions are possible.

The apparatus in FIGS. 3 and 4 shows the provision of a head detectorswitch 68 mounted near, e.g., mounted by, the applicator 60 and operableto switch its state only upon achievement of positive contact of theapplicator 60 with the animal's head 50 at the application point 51.Initially, the switch 68 can function to stop operation of the mechanismused to relatively raise the animal's head to the applicator 60 beforethe stunning operation. However, the switch 68 can also serve to switchits state only upon achievement of positive sealing contact of theapplicator with the animal's head sufficient to minimize or preventmicrowave leakage at the application point. In particular, the switch 68can be positioned so that its extremity 69, which is pressed to changethe state of the switch, requires deformation of the flexible peripheralportions 63 of the applicator 60 defining the opening 62 to an extentachieved when close contact of the applicator with the surface of theanimal's head at the application point has been achieved. The switch 68is connected in a circuit of the controller 40, which preventscommencement of application of microwaves to the animal's head until theswitch has changed its state indicative of effective sealing contact ofthe applicator with the animal's head.

A further enhancement of the apparatus to help ensure sealing of theapplicator 60 to the surface of the animal's head 50 at the applicationpoint 51 so as the minimize the leakage of microwave radiation at thatpoint, is the provision of a light sensor 67 illustrated schematicallyin FIG. 4 located within or close to the opening 62 and operative todetect any significant light entering the opening around the peripheralportion 63. Such light entry would indicate that a suitable seal of theapplicator against the animal's head against microwave leakage may notbe achieved. The controller 40 can be connected to the light sensor 67similarly to the head detector switch 68 to prevent microwaveapplication if there is likely to be a microwave leakage as indicated bythe light detection.

As shown in FIG. 2, the stunning station 10 includes a microwaveshielding 80 surrounding at least the position of the animal head 50when the animal is in its confined position. The shielding 80 forms aFaraday cage for limiting or preventing leakage of microwave radiation.The animal's head 50 in use extends through the opening 20, whichconstitutes an opening into the Faraday cage. The head end 17,particularly the panels 21, 22, effectively form part of the Faradaycage. In FIG. 3, the shielding 80 forming the Faraday cage surrounds theentire stunning station 10 and includes the access door 12, which has anassociated system safety switch 81 that must be closed (indicatingcomplete closure of the Faraday cage) before the controller can activatethe stunning cycle. An emergency stop switch 82 is located inside theFaraday cage for use if a person is ever inadvertently inside the cagewhen microwave generation starts or is about to be started. Other safetyfeatures can include warning lights on the generator and on the cagethat brightly flash to alert operators when microwaves are beinggenerated. A microwave radiation detector outside the cage can shut downthe generator if it detects radiation indicating the Faraday cage isleaking. An exhaust shown in FIG. 3 extends from the vicinity of thelocation of the animal head to extract steam and dust away from theapplicator. A quartz window can be installed inside the waveguidebetween the auto-tuner and the applicator to protect the auto-tuner andmagnetron from dust and unlikely plasma formation. Water cooling systemsare associated with the generator and the auto-tuner. An arc detectorcan be installed inside the waveguide to shut off the generator if itdetects plasma or arc formation.

An operator stationed at the controller 40 can receive all system dataand information enabling monitoring and control of the stunningoperations. The system monitoring includes verification that the animalhas been loaded into the cage and applicator positioned so the headproximity switch has switched states, and the Faraday cage door switchindicates door closure. The operator can then perform a visualinspection to ensure no personnel are in the cage and the animal head iscorrectly positioned. The information about each animal presented can beused by the operator to set the stun parameters, particularly the timeand/or power of microwave application. This can be an “effective” timethat the controller then adjusts automatically as described earlier toallow for auto-tuner delay in impedance matching. The apparatus may alsoinclude an automatic timer control (not shown) to start and terminatethe application of microwave radiation to the animal head depending onprogrammed criteria. For example, the knocking box may include an animalweight sensor, the output of which is fed to the timer control, which istaken into account in determining the necessary period for theapplication of microwaves according to an algorithm or formula.

The microwave generator 75 may be generally conventional in constructionand operation. The frequency of the microwave radiation generated andtransmitted through the associated waveguide may be any suitable value.Tests involving the application of microwave radiation to cattle andsheep heads have utilized microwave generators operating at frequenciescommercially utilized in Australia, namely 922 MHz and 2.45 GHz. Thesetests demonstrated that with the lower frequency 922 MHz, there isbetter penetration of the energy and less unwanted heating of tissues atthe surface and in surrounding tissues, so such a lower frequency ispreferred. Other countries use different microwave frequencies, e.g.,896 MHz in UK and 915 MHz in US. These would be effective also. Theoptimum frequency or frequency range can be determined empirically andis believed to be in the range 500 MHz-1 GHz.

WO2011/137497 describes considerations regarding the power requirementsof the microwave generator and aspects of the modes of microwaveradiation being generated and used, and reference may be made to thatspecification for additional data.

Preferably, the temperature rise of the frontal portion of the brain toinduce reversible unconsciousness and insensibility is in the range ofabout 5° C. to less than about 10° C. For example, tests with live(anesthetized) sheep showed frontal brain heating to about 43° C.produced electroencephalogram (EEG) traces similar to those observedwith electric stunning now widely used in abattoirs, thus indicatingthat that temperature would achieve unconsciousness and insensibility.However, heating to about 50° C. or more would start to produce proteindenaturation and, hence, permanent tissue damage.

Upon the application of the microwave energy and achievement of therequired degree of heating, the generation of microwave energy ispreferably switched off (or otherwise stopped from application to theanimal) so as to prevent further heating, particularly if the stun is tobe deemed reversible. Timely discontinuance of the application ofmicrowave energy limits or prevents heating of deeper tissues,particularly the brain stem, to any significant extent, particularlyheating to cause irreversible effects. In particular, heating of the midand deep brain tissues, and particularly the brain stem area (whichcontrols cardiac and respiratory functions), to the same extent as thefrontal portion is undesirable, because it may cause immediate effects,such as heart failure, which may then lead to the stun and subsequentslaughter being deemed non-compliant with the religious ritual slaughtercriteria, the animal carcass being rejected as unacceptable for theintended consumption by the relevant religious group, with consequentdevaluation of the carcass and its meat. In the case of sheep, brainstem heating should be limited to maintain the brain stem temperature toless than about 43° C.

Confinement of the major heating effect to the frontal portion of theanimal brain in the process and apparatus of the present disclosure isrequired to render the induced insensibility reversible. The frontalportion of the brain is involved in cognitive, perception, sensory, andconsciousness brain functioning or processes so that warming of thisportion of the brain by the extent indicated, leads to unconsciousnessand insensibility but without causing irreversible damage to the braintissues and brain functioning if the elevated temperature does notexceed 50° C.

However, although particularly developed and described herein inrelation to reversible stunning for ritual slaughter, the apparatus andmethod may be useful for other processes requiring reversibleinsensibility. Examples may include veterinary procedures in whichtemporary insensibility is required or useful. To avoid the animalregaining consciousness, the microwave radiation may be applied inpulses or intermittently to maintain unconsciousness without permanentdamage or other undesired effects. Analogously, the apparatus and methodmay be useful for other animal processes or treatments or inspections,e.g., docking, tagging, branding, and inspections generally.

Because stunning using this apparatus and process can produceinsensibility or unconsciousness in a manner without excessive stressand pain, the disclosure can be extended for use as a permanent orirreversible stunning or killing system. By increasing the power orduration of the application of microwaves, the increased heating effectand/or deeper brain heating can enable a useful alternative to currentirreversible electrical or percussive stunning of animals for slaughter.

It will be seen that the process and apparatus according to thepreferred embodiments described herein, including those described inrelation to the drawings, can enable stunning of animals, particularlyanimals for slaughter, so as to rapidly induce unconsciousness andinsensibility, enabling further processing or handling, includingslaughter in a manner compliant with religious ritual criteria orhandling for temporary processes, such as veterinary, because the stunis reversible. The stun also is carried out in a way that complies withgood animal welfare handling practices. Indeed, the disclosed method andapparatus are potentially capable of being better than currentpractices, particularly relating to animal welfare outcomes. Forexample, success rates for rapid and reliable stunning may be better,there may be less risk of operator error, and there may be less stressto animals. The present disclosure provides a combination of processesand constructions and operations of apparatus that individually andcumulatively enhance substantially the effective microwave coupling andenergy transfer to the animal's head, so that stun time can be minimizedwith great benefits in animal welfare, worker health and safety, processmonitoring and recording for regulatory and commercial purposes.

The invention claimed is:
 1. An animal stunning apparatus for inducingunconsciousness and insensibility of a live subject animal, theapparatus comprising: an applicator relatively movable in relation tothe live subject animal's head for bringing the applicator into contactwith an application point defined on the animal's head overlying afrontal portion of the animal's brain, the applicator having a couplingconformation to couple microwave radiation therethrough to the head andto the frontal portion of the brain of the subject animal when incontact with the application point on the animal's head; a microwavegenerator for generating and radiating microwave energy of a suitablepower level and frequency; a waveguide located to receive and direct themicrowave radiation from the generator to the applicator located at anoperative end of the waveguide to heat the frontal portion of the brainof the subject animal beneath the application point which the applicatorcontacts in use; an auto-tuner operatively associated with the waveguideand configured to detect reflected power of microwave radiation in thewaveguide resulting from the degree of the impedance matching betweenthe applicator and the animal's head and which tunes the waveguide toreduce the reflected power and increase the transfer of microwave powerto the animal's head; a monitoring device comprising at least one of: avisual display responsive to operation of the generator and theauto-tuner and operative to display the microwave power being generatedin use by the microwave generator to enable monitoring of an effectivepower transfer to the animal's head and visual assessment of aneffective syncope; or a memory device operative to continually logduring the operation of the apparatus the microwave power beinggenerated by the microwave generator to provide a stored record ofparameters of an animal stunning operation for subsequent analysis forregulatory compliance, process research, and operation managementpurposes; wherein the microwave power is determined from the generatedmicrowave energy and the reflected power as being transferred throughthe applicator operation; and a switch operable to discontinue theapplication of microwave radiation effecting heating of the frontalportion of the brain after a period of time sufficient to raise thetemperature of the frontal portion of the brain of the subject animal tothereby induce the unconsciousness and insensibility.
 2. The apparatusof claim 1, wherein the auto-tuner is operable in an iterative manner tocontinually tune the waveguide during the application of the microwaveradiation to continually improve or maintain impedance matching whilethe impedance of the animal's head changes due to heating.
 3. Theapparatus of claim 1, wherein the applicator has an opening therein forcoupling the microwave radiation from the waveguide to the animal's headat the application point, the peripheral portions of the applicatordefining the opening contacting the animal's head to surround theapplication point when the applicator is in its operative position. 4.The apparatus of claim 3, wherein the peripheral portions of theapplicator are yieldable in order to be configured to conform in shapeto the shape of the animal's head at the application point upon relativeoperative positioning of the applicator at the application point.
 5. Theapparatus of claim 4, wherein the peripheral portions of the applicatorare configured to conform to the surface shape of the animal's head atthe application point, the peripheral portions of the applicator beingimpermeable to microwave radiation.
 6. The apparatus of claim 5, whereinthe peripheral portions of the applicator defining the opening areflexible in order to be configured to conform to the surface shape, tobe impermeable to microwave radiation, and to be resilient tosubstantially return to an initial state after relative separation ofthe applicator from the application point.
 7. The apparatus of claim 6,wherein the peripheral portions of the applicator defining the openingare composed of metallic braid.
 8. The apparatus of claim 3, wherein thewaveguide or applicator includes a movable joint or section enablinglimited movement of the applicator to improve contact of the peripheralportions of the applicator defining the opening for different relativepositions and conformations of the animal's head and to limit microwaveleakage at the application point.
 9. The apparatus of claim 8, whereinthe moveable joint or section is configured to enable limited movementof the applicator about two orthogonal axes which are generally parallelto the surface of the animal's head at the application point where theanimal's head is located for contact with the applicator.
 10. Theapparatus of claim 9, further comprising a head detector switch mountedby the applicator and operable to switch its state only upon achievementof positive sealing contact of the applicator with the animal's head atthe application point.
 11. The apparatus of claim 10, wherein the headdetector switch is configured to switch states only upon deformation offlexible peripheral portions of the applicator being flexed to an extentachieved when close contact of the applicator with the surface of theanimal's head at the application point has been achieved, the switchbeing connected in a circuit preventing application of microwaveradiation to the animal's head until the switch has changed its stateindicative of effective sealing contact of the applicator with theanimal's head.
 12. An animal stunning apparatus for inducingunconsciousness and insensibility of a live subject animal, theapparatus comprising: an applicator relatively movable in relation tothe live subject animal's head for bringing the applicator into contactwith an application point defined on the animal's head overlying afrontal portion of the animal's brain, the applicator having a couplingconformation to couple microwave radiation therethrough to the head andto the frontal portion of the brain of the subject animal when incontact with the application point on the animal's head; a microwavegenerator for generating and radiating microwave energy of a suitablepower level and frequency; a waveguide located to receive and direct themicrowave radiation from the generator to the applicator located at anoperative end of the waveguide to heat the frontal portion of the brainof the subject animal beneath the application point which the applicatorcontacts in use; an auto-tuner operatively associated with the waveguideand configured to detect reflected power of microwave radiation in thewaveguide resulting from the degree of the impedance matching betweenthe applicator and the animal's head and which tunes the waveguide toreduce the reflected power and increase the transfer of microwave powerto the animal's head; a visual display responsive to operation of thegenerator and the auto-tuner and operative to display the microwavepower being generated in use by the microwave generator to enablemonitoring of an effective power transfer to the animal's head andvisual assessment of an effective syncope, wherein the microwave poweris determined from the generated microwave energy and the reflectedpower as being transferred through the applicator operation; a memorydevice operative to continually log during the operation of theapparatus the microwave power being generated by the microwave generatorto provide a stored record of parameters of an animal stunning operationfor subsequent analysis for regulatory compliance, process research, andoperation management purposes; and a switch operable to discontinue theapplication of microwave radiation effecting heating of the frontalportion of the brain after a period of time sufficient to raise thetemperature of the frontal portion of the brain of the subject animal tothereby induce the unconsciousness and insensibility.
 13. A method ofstunning an animal for inducing unconsciousness and insensibility of theanimal, the method comprising: locating an applicator in contact with anapplication point on the animal's head immediately overlying the frontalportion of the subject animal's brain, the applicator having a couplingconformation to couple microwave radiation through the applicator to thehead and to the frontal portion of the brain of the subject animal;generating microwave radiation of a suitable power level and frequencyand directing the radiation through a waveguide to the applicator at anoperative end of the waveguide to heat the frontal portion of the brainof the subject animal; detecting reflected power of microwave radiationin the waveguide and, in response to the level of the reflected power,tuning the waveguide so as to reduce the reflected power being detectedby changing the impedance of the waveguide and the applicator tosubstantially conform with the impedance of the head and therebyincrease the transfer of microwave power to the head; visuallydisplaying during the stunning operation the microwave power beinggenerated by the microwave generator, the microwave power being detectedas reflected within the waveguide and arising from the degree of theimpedance matching with the head, and the power determined from thegenerated and reflected power as being transferred through theapplicator throughout the stunning operation thereby enabling visualmonitoring of the effective power transfer and visual assessment of aneffective syncope of the animal; continually logging during the stunningoperation the microwave power being generated by the microwavegenerator, the microwave power being detected as reflected within thewaveguide and arising from the degree of the impedance matching with thehead, and the power determined from the generated and reflected power asbeing transferred through the applicator throughout the stunningoperation so as to provide a stored record of parameters of the stunningoperation for subsequent analysis for regulatory compliance, processresearch, and operation management purposes; and continuing theapplication of the microwave radiation to effect the heating for aperiod of time to raise the temperature of the frontal portion of thebrain, the period being sufficient to induce insensibility.
 14. Themethod according to claim 13, further comprising positioning theapplicator in contact with the application point that is mediallylocated on the head of the subject animal above a line extending betweenthe animal's eyes so as to be located at the closest external point tothe central and frontal portion of the brain.
 15. The method accordingto claim 13, further comprising heating the frontal portion of the brainof the subject animal until at least one of the conditions: thetemperature increases by an amount in the range of about 5° C. to about10° C.; or the temperature increases to about 43° C.
 16. The methodaccording to claim 13, wherein a period of time during which applicationof the microwave radiation is continued and during which the tuning iscontinually performed is terminated after a period for an effectivepower transfer defined as sufficient for an effective syncope of theanimal, the effective power transfer being determined as a function ofpower transferred to the animal's head excluding reflected power. 17.The method according to claim 16, further comprising: continuallymeasuring the power of microwave radiation being reflected; anddetermining from the power generated by the microwave generator and fromthe measured reflected power the actual power being transferred throughthe applicator to the animal's head.
 18. The method according to claim17, wherein the effective power transfer is reached by applyingmicrowave power for a predetermined time period which is started onlyafter the power being transferred through the applicator is determinedto have reached a predetermined level.
 19. The method according to claim17, wherein the effective power transfer is reached by applyingmicrowave power for a time period sufficient for the sum of thedetermined power levels being transferred through the applicator for aplurality of time increments reaches a predetermined sum.
 20. The methodaccording to claim 17, wherein the detection of microwave radiationreflected in the waveguide is performed using a directional couplerassociated with the waveguide and operable to measure the complexreflection coefficient of the load thereby enabling determination inreal time of the power being transferred through the applicator.